The levelling screed should be finished to suit the type of flooring The finished surface should be free from excessive dusting and friability.
Although the aim is to achieve both the necessary flatness and surface texture, this might not be possible for some thin sheet and tile floor coverings with a screed containing sand. Likewise, fine concrete screed containing aggregate of up to 10 mm maximum size and of low moisture content does not produce an acceptable surface texture for these types of floor coverings. In such cases, the levelling screed should be finished by applying a smoothing compound (“underlayment” in BS 8203) to the hardened screed as part of the floor covering system just before laying the floor covering. A smoothing compound should not be used on a weak or friable levelling screed.